Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;
@SuppressWarnings("unused")
public class Solution { //Название класса здесь
	private static boolean IOTypeIsFile = false; //Вид ввода/вывода. true-через файл. false-через консоль.
	private static String FileInput = ""; //Название файла ввода
	private static String FileOutput = "";//Название файла вывода
	private static Scanner in;
	private static PrintStream out,err;
	private static String ts(Object a) {return String.valueOf(a);}
	private static int ti(String a) {return Integer.valueOf(a);}
	private static double td(String a) {return Double.valueOf(a);}
	private static int[] arrayI(int n) {int[] ans = new int[n];
		for(int i = 0; i < n; ++i) {ans[i] = in.nextInt();}return ans;
	}
	private static String[] arrayS(int n) {String[] ans = new String[n];
		for(int i = 0; i < n; ++i) {ans[i] = in.next();}return ans;
	}
	private static double[] arrayD(int n) {double[] ans = new double[n];
		for(int i = 0; i < n; ++i) {ans[i] = in.nextDouble();}return ans;
	}
	private static void SomeVeryLargeUndUselessFunctionName() {if (!IOTypeIsFile) {err.print(FileInput+FileOutput);}}
	public static void main(String[] args) {
		err=new PrintStream(System.err);
		if(IOTypeIsFile) {
			File f = new File(FileInput);
			try {
				in = new Scanner(f);
				out = new PrintStream(FileOutput);
			} catch (FileNotFoundException var3) {System.err.println("404");}
		} else {
			in = new Scanner(System.in);
			out = new PrintStream(System.out);
		}
		run();
		in.close();
		out.close();
	}
	//Код пишут отсюда
	/*
3 3
0 1 0
1 4 1
0 1 0
*/
	private static void run() {
		int n=in.nextInt(),m=in.nextInt(),min=-1;
		int[][] table=new int[n][m];
		HashSet<Integer> trow=new HashSet<>(),tcol=new HashSet<>();
		for (int i=0;i<n;i++) {
			for (int j=0;j<m;j++) {
				table[i][j]=in.nextInt();
				if ((table[i][j]<min)||(min==-1)) {min=table[i][j];}
				if (table[i][j]==0) {trow.add(i);tcol.add(j);}
			}
		}
		ArrayList<String> ans=new ArrayList<>();
		if (min>0) {
			if (n<m) {
				for (int i=0;i<n;i++) {
					for (int j=0;j<min;j++) {ans.add("row "+ts(i+1));}
					for (int j=0;j<m;j++) {
						table[i][j]-=min;
						if (table[i][j]==0) {trow.add(i);tcol.add(j);}
					}
				}
			} else {
				for (int j=0;j<m;j++) {
					for (int i=0;i<min;i++) {ans.add("col "+ts(j+1));}
					for (int i=0;i<n;i++) {
						table[i][j]-=min;
						if (table[i][j]==0) {trow.add(i);tcol.add(j);}
					}
				}
			}
		}
		do {
			for (int i:trow) {
				for (int j=0;j<m;j++) {
					if (table[i][j]>0) {
						min=-1;
						for (int l=0;l<n;l++) {
							if ((table[l][j]<min)||(min==-1)) {min=table[l][j];}
						}
						if (min==0) {out.println(-1);return;}
						for (int l=0;l<min;l++) {ans.add("col "+ts(j+1));}
						for (int l=0;l<n;l++) {table[l][j]-=min;}
					}
				}
			}
			for (int i:tcol) {
				for (int j=0;j<n;j++) {
					if (table[j][i]>0) {
						min=-1;
						for (int l=0;l<m;l++) {
							if ((table[j][l]<min)||(min==-1)) {min=table[j][l];}
						}
						if (min==0) {out.println(-1);return;}
						for (int l=0;l<min;l++) {ans.add("row "+ts(j+1));}
						for (int l=0;l<m;l++) {table[j][l]-=min;}
					}
				}
			}
			trow.clear();
			tcol.clear();
			for (int i=0;i<n;i++) {
				for (int j=0;j<m;j++) {
					if (table[i][j]==0) {trow.add(i);tcol.add(j);}
				}
			}
		} while ((trow.size()<n)||(tcol.size()<m));
		for (int[]ints:table){
			for (int j:ints){if (j!=0){out.println(-1);return;}}
		}
		out.println(ans.size());
		for (String string:ans) {out.println(string);}
	}
}